Grinding wheel, particularly for grinding work at a high feed speed

ABSTRACT

A grinding wheel is described, particularly for grinding work at a high feed speed, including a discoid body between the axially opposed faces of which an outside wall of cylindrical profile is defined, bearing the abrasive grinding material. The abrasive material is disposed circumferentially on the outside wall without a gap. The grinding wheel also includes a plurality of ducts extending radially in the discoid body, opening onto the outside wall and also passing through the abrasive material, so as to constitute ducts for conveying a cooling and/or lubricating liquid onto the abrasive outer surface of the outside wall.

TECHNICAL FIELD

The present invention concerns a grinding wheel particularly designed for grinding work at a high feed speed, having the characteristics mentioned in the preamble of the main claim.

TECHNOLOGICAL BACKGROUND

In the relevant technical field grinding wheels made of abrasive material are known which are designed for grinding work at a high feed speed. A typical process of the aforesaid type is that relating to the grinding of the edges of windows for motor vehicles. In these processes the feed speed reaches high levels, for example from 14 m/min. to 36 m/min., this range being cited solely by way of example.

The particular nature of the grinding work also requires an abrasive surface of the grinding wheel, that surface which comes into contact with the workpiece to be subjected to grinding, extending continuously over the cylindrical outside wall of the body of the grinding wheel.

When using grinding wheels of the type indicated, in order to reduce chipping of the glass being processed and increase the service life of the tool, provision is made for the use of lubricating and/or cooling liquids, conveyed in the region of the point of working contact.

DESCRIPTION OF THE INVENTION

The principal aim of the invention is that of providing a grinding wheel structurally and functionally designed to obtain improved distribution of the cooling/lubricating liquid in the area of contact with the workpiece being processed, in order to convey the liquid more homogeneously and to obtain, even in the case of high feed speeds of the grinding wheel, a greater reduction in chipping of the workpieces being processed and a longer service life of the tool, compared with known solutions.

This aim is achieved by the invention by means of a grinding wheel produced according to the following claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the invention will become clearer from the following detailed description of a preferred exemplary embodiment thereof, illustrated by way of non-limiting example with reference to the appended drawings, in which:

FIG. 1 is a perspective view from above of a grinding wheel produced according to the invention;

FIG. 2 is an axial half section view of the grinding wheel of FIG. 1,

FIG. 3 is a view on an enlarged scale of the detail indicated by the arrow A in FIG. 2,

FIG. 4 is a partial perspective view, on an enlarged scale compared with FIG. 2, of a detail of the grinding wheel of FIG. 1.

PREFERRED EMBODIMENT OF THE INVENTION

With reference to the drawings mentioned, the reference 1 indicates as a whole a grinding wheel designed for grinding work at a high feed speed, which is produced according to the present invention.

The grinding wheel 1 comprises a discoid body 2, axially symmetrical with respect to a main axis X, about which the grinding wheel can be set in rotation in the processing stages.

The discoid body 2 is provided with a central hub with through holes 3 for fixing to a drive shaft, not shown.

The discoid body 2 also extends between two axially opposed faces 2 a, 2 b, between which is defined a cylindrical outside wall 4 bearing the abrasive material suitable for the grinding operations.

In more detail, in the outside wall 4 a seat 5 is provided which runs circumferentially, and wherein the abrasive material 6 is disposed, the material appearing on the cylindrical outside wall with an abrasive surface, indicated by 6 a, which extends circumferentially, without a gap, in the region of the outside wall 4.

Preferably, the surface 6 a has in axial section (FIG. 2) a curved transverse profile with a concavity facing towards the workpiece (not shown) to be subjected to grinding. The profile is designed for the grinding of corresponding edges with convex profile, such as those provided on the peripheral edges of the windows of motor vehicles, the grinding of which is conveniently carried out with the grinding wheel of the invention.

According to a principal characteristic of the invention, the grinding wheel comprises a plurality of ducts 7, extending radially in the discoid body 2, and one of which can be seen in section in FIG. 2 (this figure shows a half section, by reason of the axial symmetry). Only one of the ducts 7 will be described in detail hereinafter, since they are identical in structure and function.

Each duct 7 extends radially in the body 2 for a radial portion extending between a first end 7 a, at which the duct opens into the surface 6 a of the outside wall 4, and an opposed end 7 b, communicating with a cavity or recess 8. Said recess has an annular configuration and extends circumferentially on the face 2 a of the disc, coaxially with the axis X.

On the face 2 a of the disc, the recess 8 opens to the outside via a mouth 8 a in the shape of an annular rim concentric with the axis X.

The volume of the recess 8 is selected to be such that the cavity forms a kind of reservoir of predetermined capacity, fed via a stationary delivery duct (not shown) supplying a flow of liquid to the inside of the recess, via the mouth 8 a. The capacity of the recess 8 ensures that in each duct 7 a corresponding quantity of liquid is distributed homogeneously, and is then conveyed by centrifugal action (during the rotation of the disc) from the ducts 7 onto the abrasive surface 6 a, thus ensuring the homogeneous distribution of liquid onto the surface itself.

The liquid may consist of a lubricating or cooling liquid or, as a further alternative, of a liquid having both lubricating and cooling properties. A preferred example provides for the liquid to be water.

Through the centrifugal action due to the speed of rotation, the liquid is then brought, homogeneously distributed, to the point of contact between the abrasive surface 6 a and the workpiece to be ground.

It should also be noted that the ducts 7 are provided so as to pass through the abrasive material 6, until they reach the end section communicating with the outside of the outside wall 4.

The ducts 7 conveniently have a cross-section of circular shape (for example are produced as simple radial through holes) or of elliptical shape or, as a further alternative, may have a cross-section of polygonal, for example rectangular, shape.

The number and dimension of the ducts provided in the discoid body 2 may further vary according to specific requirements and to the rotation speeds or the feed speeds provided for conducting the grinding wheel 1 in the grinding phases, and also according to the dimensions of the grinding wheel and of the window edge to be subjected to grinding.

A preferred example provides for twelve ducts 7 disposed at a regular angular pitch and having a circular cross-section, as shown in FIG. 2.

The invention thus achieves the aims proposed, obtaining the advantages claimed above with reference to the prior art.

A principal advantage lies in the fact of being able to obtain, in grinding wheels at high feed speeds, a distribution of cooling/lubricating liquid of improved homogeneity, with which it is possible to obtain a greater reduction in chipping of the ground window in addition to a longer service life of the grinding wheel. This is particularly noticeable with particularly high feed speeds, also in ranges from 14 m/min. up to 36 m/min. 

1. A grinding wheel, particularly for grinding work at a high feed speed, comprising a discoid body (2) between axially opposed faces (2 a,2 b) of which an outside wall (4) of a cylindrical profile is defined, bearing an abrasive grinding material, and wherein the abrasive material is disposed circumferentially on said outside wall without a gap, the wheel further comprising a plurality of ducts (7) extending radially in the discoid body (2), opening onto the outside wall (4) and also passing through said abrasive material, so as to constitute ducts for conveying a cooling and/or lubricating liquid onto the abrasive outer surface of said outside wall (4).
 2. A grinding wheel according to claim 1, wherein each of the ducts (7) of said plurality comprises a radial portion extending from a first end (7 a) opening into the outside wall (4) of the discoid body and a second, opposed end (7 b) opening into an annular recess (8) provided on one (2 a) of the opposed faces of said body (2), said recess (8) having a volume such as to receive a predetermined quantity of said liquid suitable for being conveyed in homogenous distribution and by centrifugal action along said ducts (7) until the liquid reaches the abrasive surface of the grinding wheel.
 3. A grinding wheel according to claim 1, wherein said ducts (7) are angularly spaced at a regular pitch in the discoid body (2).
 4. A grinding wheel according to claim 1, wherein said ducts (7) have a cross-section of circular or elliptical shape.
 5. A grinding wheel according to claim 1, wherein said ducts (7) have a cross-section of quadrilateral polygonal shape.
 6. A grinding wheel according to claim 1, wherein the abrasive material is disposed in a continuous seat extending circumferentially on the discoid body (2) and opening into the outside wall (4) of said body, said ducts (7) extending in communication with said seat and also passing through the abrasive material provided in said seat.
 7. A grinding wheel according to claim 6, wherein the abrasive surface (6 a), capable of contact with a workpiece to be subjected to grinding, has in axial section a concave curved profile for contact with corresponding convex profiles of workpieces to be subjected to grinding.
 8. A grinding wheel according to claim 7, wherein said concave profile of the abrasive surface (6 a) is selected for the grinding of convex edges of windows for motor vehicles, wherein said grinding wheel is driven at a high feed speed with respect to said edges.
 9. A grinding wheel according to claim 2, wherein each of said ducts (7) extends with its respective radial portion as far as a predetermined distance from the main grinding wheel axis, at which it is connected in fluid communication with said recess (8).
 10. A grinding wheel, particularly for grinding work at a high feed speed, comprising a discoid body (2) between axially opposed faces (2 a,2 b) of which an outside wall (4) of a cylindrical profile is defined, bearing an abrasive grinding material, and wherein the abrasive material is disposed circumferentially on said outside wall without a gap, the wheel further comprising a plurality of ducts (7) extending radially in the discoid body (2), opening onto the outside wall (4) and also passing through said abrasive material, so as to constitute ducts for conveying a cooling and/or lubricating liquid onto the abrasive outer surface of said outside wall (4), wherein each of the ducts (7) of said plurality comprises a radial portion extending from a first end (7 a) opening into the outside wall (4) of the discoid body and a second, opposed end (7 b) opening into an annular recess (8) provided on one (2 a) of the opposed faces of said body (2), said recess (8) having a volume such as to receive a predetermined quantity of said liquid suitable for being conveyed in homogenous distribution and by centrifugal action along said ducts (7) until the liquid reaches the abrasive surface of the grinding wheel.
 11. A grinding wheel according to claim 10, wherein said ducts (7) are angularly spaced at a regular pitch in the discoid body (2).
 12. A grinding wheel according to claim 10, wherein said ducts (7) have a cross-section of circular or elliptical shape.
 13. A grinding wheel according to claim 10, wherein said ducts (7) have a cross-section of quadrilateral polygonal shape.
 14. A grinding wheel according to claim 10, wherein the abrasive material is disposed in a continuous seat extending circumferentially on the discoid body (2) and opening into the outside wall (4) of said body, said ducts (7) extending in communication with said seat and also passing through the abrasive material provided in said seat. 